package com.stars.easyms.base.util;

import com.stars.easyms.base.constant.EasyMsCommonConstants;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;

import javax.servlet.http.HttpServletRequest;

/**
 * <p>className: IPUtils</p>
 * <p>description: Ip工具类</p>
 *
 * @author sungaoang
 * @version 1.6.2
 * @date 2020/9/4 8:59 上午
 */
@Slf4j
public final class IPUtils {

    /**
     * 获取IP地址
     * <p>
     * 使用Nginx等反向代理软件， 则不能通过request.getRemoteAddr()获取IP地址
     * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，X-Forwarded-For中第一个非unknown的有效IP字符串，则为真实IP地址
     */
    public static String getIpAddr(HttpServletRequest request) {
        String ip = null;
        try {
            ip = request.getHeader("x-forwarded-for");
            if (StringUtils.isEmpty(ip) || EasyMsCommonConstants.UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("Proxy-Client-IP");
            }
            if (StringUtils.isEmpty(ip) || ip.length() == 0 || EasyMsCommonConstants.UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
            }
            if (StringUtils.isEmpty(ip) || EasyMsCommonConstants.UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
            }
            if (StringUtils.isEmpty(ip) || EasyMsCommonConstants.UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
            }
            if (StringUtils.isEmpty(ip) || EasyMsCommonConstants.UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
            }
            if (ip != null) {
                //对于通过多个代理的情况，最后IP为客户端真实IP,多个IP按照','分割
                int position = ip.indexOf(",");
                if (position > 0) {
                    ip = ip.substring(0, position);
                }
            }
        } catch (Exception e) {
            log.error("IPUtils ERROR ", e);
        }

        return ip;
    }

    private IPUtils() {
    }

}
